yplib.c

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/*
 * Copyright (c) 1992/3 Theo de Raadt <[e-mail]>
 * Copyright (c) 1998 Bill Paul <[e-mail]>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote
 *    products derived from this software without specific prior written
 *    permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef LINT
static char *rcsid = "$Id: yplib.c,v 1.30 1998/03/07 05:06:10 wpaul Exp $";
#endif

#include <sys/param.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/file.h>
#include <sys/uio.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <rpc/rpc.h>
#include <rpc/xdr.h>
#include <rpcsvc/yp.h>

/*
 * We have to define these here due to clashes between yp_prot.h and
 * yp.h.
 */

#define YPMATCHCACHE

#ifdef YPMATCHCACHE
struct ypmatch_ent {
        char			*ypc_map;
	keydat			ypc_key;
	valdat			ypc_val;
        time_t			ypc_expire_t;
        struct ypmatch_ent	*ypc_next;
};
#define YPLIB_MAXCACHE	5	/* At most 5 entries */
#define YPLIB_EXPIRE	5	/* Expire after 5 seconds */
#endif

struct dom_binding {
        struct dom_binding *dom_pnext;
        char dom_domain[YPMAXDOMAIN + 1];
        struct sockaddr_in dom_server_addr;
        u_short dom_server_port;
        int dom_socket;
        CLIENT *dom_client;
        u_short dom_local_port; /* now I finally know what this is for. */
        long dom_vers;
#ifdef YPMATCHCACHE
	struct ypmatch_ent *cache;
	int ypmatch_cachecnt;
#endif
};

#include <rpcsvc/ypclnt.h>

#ifndef BINDINGDIR
#define BINDINGDIR "/var/yp/binding"
#endif
#define MAX_RETRIES 20

extern bool_t xdr_domainname(), xdr_ypbind_resp();
extern bool_t xdr_ypreq_key(), xdr_ypresp_val();
extern bool_t xdr_ypreq_nokey(), xdr_ypresp_key_val();
extern bool_t xdr_ypresp_all(), xdr_ypresp_all_seq();
extern bool_t xdr_ypresp_master();

int (*ypresp_allfn)();
void *ypresp_data;

static void _yp_unbind __P(( struct dom_binding * ));
struct dom_binding *_ypbindlist;
static char _yp_domain[MAXHOSTNAMELEN];
int _yplib_timeout = 10;

#ifdef YPMATCHCACHE
static void ypmatch_cache_delete(ypdb, prev, cur)
	struct dom_binding	*ypdb;
	struct ypmatch_ent	*prev;
	struct ypmatch_ent	*cur;
{
	if (prev == NULL)
		ypdb->cache = cur->ypc_next;
	else
		prev->ypc_next = cur->ypc_next;

	free(cur->ypc_map);
	free(cur->ypc_key.keydat_val);
	free(cur->ypc_val.valdat_val);
	free(cur);

	ypdb->ypmatch_cachecnt--;

	return;
}

static void ypmatch_cache_flush(ypdb)
	struct dom_binding	*ypdb;
{
	struct ypmatch_ent	*n, *c = ypdb->cache;

	while (c != NULL) {
		n = c->ypc_next;
		ypmatch_cache_delete(ypdb, NULL, c);
		c = n;
	}

	return;
}

static void ypmatch_cache_expire(ypdb)
	struct dom_binding	*ypdb;
{
	struct ypmatch_ent	*c = ypdb->cache;
	struct ypmatch_ent	*n, *p = NULL;
	time_t			t;

	time(&t);

	while (c != NULL) {
		if (t >= c->ypc_expire_t) {
			n = c->ypc_next;
			ypmatch_cache_delete(ypdb, p, c);
			c = n;
		} else {
			p = c;
			c = c->ypc_next;
		}
	}

	return;
}

static void ypmatch_cache_insert(ypdb, map, key, val)
	struct dom_binding	*ypdb;
	char			*map;
	keydat			*key;
	valdat			*val;
{
	struct ypmatch_ent	*new;

	/* Do an expire run to maybe open up a slot. */
	if (ypdb->ypmatch_cachecnt)
		ypmatch_cache_expire(ypdb);

	/*
	 * If there are no slots free, then force an expire of
	 * the least recently used entry.
 	 */
	if (ypdb->ypmatch_cachecnt >= YPLIB_MAXCACHE) {
		struct ypmatch_ent	*o = NULL, *c = ypdb->cache;
		time_t			oldest = 0;

		oldest = ~oldest;

		while(c != NULL) {
			if (c->ypc_expire_t < oldest) {
				oldest = c->ypc_expire_t;
				o = c;
			}
			c = c->ypc_next;
		}

		if (o == NULL)
			return;
		o->ypc_expire_t = 0;
		ypmatch_cache_expire(ypdb);
	}

	new = malloc(sizeof(struct ypmatch_ent));
	if (new == NULL)
		return;

	new->ypc_map = strdup(map);
	if (new->ypc_map == NULL) {
		free(new);
		return;
	}
	new->ypc_key.keydat_val = malloc(key->keydat_len);
	if (new->ypc_key.keydat_val == NULL) {
		free(new->ypc_map);
		free(new);
		return;
	}
	new->ypc_val.valdat_val = malloc(val->valdat_len);
	if (new->ypc_val.valdat_val == NULL) {
		free(new->ypc_val.valdat_val);
		free(new->ypc_map);
		free(new);
		return;
	}

	new->ypc_expire_t = time(NULL) + YPLIB_EXPIRE;
	new->ypc_key.keydat_len = key->keydat_len;
	new->ypc_val.valdat_len = val->valdat_len;
	bcopy(key->keydat_val, new->ypc_key.keydat_val, key->keydat_len);
	bcopy(val->valdat_val, new->ypc_val.valdat_val, val->valdat_len);

	new->ypc_next = ypdb->cache;
	ypdb->cache = new;

	ypdb->ypmatch_cachecnt++;

	return;
}

static bool_t ypmatch_cache_lookup(ypdb, map, key, val)
	struct dom_binding	*ypdb;
	char			*map;
	keydat			*key;
	valdat			*val;
{
	struct ypmatch_ent	*c = ypdb->cache;

	ypmatch_cache_expire(ypdb);

	for (c = ypdb->cache; c != NULL; c = c->ypc_next) {
		if (strcmp(map, c->ypc_map))
			continue;
		if (key->keydat_len != c->ypc_key.keydat_len)
			continue;
		if (bcmp(key->keydat_val, c->ypc_key.keydat_val,
				key->keydat_len))
			continue;
	}

	if (c == NULL)
		return(FALSE);

	val->valdat_len = c->ypc_val.valdat_len;
	val->valdat_val = c->ypc_val.valdat_val;

	return(TRUE);
}
#endif

char *
ypbinderr_string(incode)
	int incode;
{
	static char err[80];
	switch(incode) {
	case 0:
		return "Success";
	case YPBIND_ERR_ERR:
		return "Internal ypbind error";
	case YPBIND_ERR_NOSERV:
		return "Domain not bound";
	case YPBIND_ERR_RESC:
		return "System resource allocation failure";
	}
	sprintf(err, "Unknown ypbind error: #%d\n", incode);
	return err;
}

int
_yp_dobind(dom, ypdb)
	char *dom;
	struct dom_binding **ypdb;
{
	static pid_t pid = -1;
	char path[MAXPATHLEN];
	struct dom_binding *ysd, *ysd2;
	struct ypbind_resp ypbr;
	struct timeval tv;
	struct sockaddr_in clnt_sin;
	int clnt_sock, fd;
	pid_t gpid;
	CLIENT *client;
	int new = 0, r;
	int retries = 0;
	struct sockaddr_in check;
	int checklen = sizeof(struct sockaddr_in);

	/* Not allowed; bad doggie. Bad. */
	if (strchr(dom, '/') != NULL)
		return(YPERR_BADARGS);

	gpid = getpid();
	if( !(pid==-1 || pid==gpid) ) {
		ysd = _ypbindlist;
		while(ysd) {
			if(ysd->dom_client != NULL)
				_yp_unbind(ysd);
			ysd2 = ysd->dom_pnext;
			free(ysd);
			ysd = ysd2;
		}
		_ypbindlist = NULL;
	}
	pid = gpid;

	if(ypdb!=NULL)
		*ypdb = NULL;

	if(dom==NULL || strlen(dom)==0)
		return YPERR_BADARGS;

	for(ysd = _ypbindlist; ysd; ysd = ysd->dom_pnext)
		if( strcmp(dom, ysd->dom_domain) == 0)
			break;


	if(ysd==NULL) {
		ysd = (struct dom_binding *)malloc(sizeof *ysd);
		bzero((char *)ysd, sizeof *ysd);
		ysd->dom_socket = -1;
		ysd->dom_vers = 0;
		new = 1;
	} else {
	/* Check the socket -- may have been hosed by the caller. */
		if (getsockname(ysd->dom_socket, (struct sockaddr *)&check,
		    &checklen) == -1 || check.sin_family != AF_INET ||
		    check.sin_port != ysd->dom_local_port) {
		/* Socket became bogus somehow... need to rebind. */
			int save, sock;

			sock = ysd->dom_socket;
			save = dup(ysd->dom_socket);
			if (ysd->dom_client != NULL)
				clnt_destroy(ysd->dom_client);
			ysd->dom_vers = 0;
			ysd->dom_client = NULL;
			sock = dup2(save, sock);
			close(save);
		}
	}

again:
	retries++;
	if (retries > MAX_RETRIES) {
		if (new)
			free(ysd);
		return(YPERR_YPBIND);
	}
#ifdef BINDINGDIR
	if(ysd->dom_vers==0) {
		/*
		 * We're trying to make a new binding: zorch the
		 * existing handle now (if any).
		 */
		if(ysd->dom_client != NULL) {
			clnt_destroy(ysd->dom_client);
			ysd->dom_client = NULL;
			ysd->dom_socket = -1;
		}
		sprintf(path, "%s/%s.%d", BINDINGDIR, dom, 2);
		if( (fd=open(path, O_RDONLY)) == -1) {
			/* no binding file, YP is dead. */
			/* Try to bring it back to life. */
			close(fd);
			goto skipit;
		}
		if( flock(fd, LOCK_EX|LOCK_NB) == -1 && errno==EWOULDBLOCK) {
			struct iovec iov[2];
			struct ypbind_resp ybr;
			u_short	ypb_port;

			iov[0].iov_base = (caddr_t)&ypb_port;
			iov[0].iov_len = sizeof ypb_port;
			iov[1].iov_base = (caddr_t)&ybr;
			iov[1].iov_len = sizeof ybr;

			r = readv(fd, iov, 2);
			if(r != iov[0].iov_len + iov[1].iov_len) {
				close(fd);
				ysd->dom_vers = -1;
				goto again;
			}

			bzero(&ysd->dom_server_addr, sizeof ysd->dom_server_addr);
			ysd->dom_server_addr.sin_family = AF_INET;
			ysd->dom_server_addr.sin_len = sizeof(struct sockaddr_in);
			ysd->dom_server_addr.sin_addr.s_addr =
			    *(u_long *)&ybr.ypbind_resp_u.ypbind_bindinfo.ypbind_binding_addr;
			ysd->dom_server_addr.sin_port =
			    *(u_short *)&ybr.ypbind_resp_u.ypbind_bindinfo.ypbind_binding_port;

			ysd->dom_server_port = ysd->dom_server_addr.sin_port;
			close(fd);
			goto gotit;
		} else {
			/* no lock on binding file, YP is dead. */
			/* Try to bring it back to life. */
			close(fd);
			goto skipit;
		}
	}
skipit:
#endif
	if(ysd->dom_vers==-1 || ysd->dom_vers==0) {
		/*
		 * We're trying to make a new binding: zorch the
		 * existing handle now (if any).
		 */
		if(ysd->dom_client != NULL) {
			clnt_destroy(ysd->dom_client);
			ysd->dom_client = NULL;
			ysd->dom_socket = -1;
		}
		bzero((char *)&clnt_sin, sizeof clnt_sin);
		clnt_sin.sin_family = AF_INET;
		clnt_sin.sin_addr.s_addr = htonl(INADDR_LOOPBACK);

		clnt_sock = RPC_ANYSOCK;
		client = clnttcp_create(&clnt_sin, YPBINDPROG, YPBINDVERS, &clnt_sock,
			0, 0);
		if(client==NULL) {
			/*
			 * These conditions indicate ypbind just isn't
			 * alive -- we probably don't want to shoot our
			 * mouth off in this case; instead generate error
			 * messages only for really exotic problems.
			 */
			if (rpc_createerr.cf_stat != RPC_PROGNOTREGISTERED &&
			   (rpc_createerr.cf_stat != RPC_SYSTEMERROR &&
			   rpc_createerr.cf_error.re_errno == ECONNREFUSED))
				clnt_pcreateerror("clnttcp_create");
			if(new)
				free(ysd);
			return (YPERR_YPBIND);
		}

		/*
		 * Check the port number -- should be < IPPORT_RESERVED.
		 * If not, it's possible someone has registered a bogus
		 * ypbind with the portmapper and is trying to trick us.
		 */
		if (ntohs(clnt_sin.sin_port) >= IPPORT_RESERVED) {
			if (client != NULL)
				clnt_destroy(client);
			if (new)
				free(ysd);
			return(YPERR_YPBIND);
		}
		tv.tv_sec = _yplib_timeout/2;
		tv.tv_usec = 0;
		r = clnt_call(client, YPBINDPROC_DOMAIN,
			xdr_domainname, (char *)&dom, xdr_ypbind_resp, &ypbr, tv);
		if(r != RPC_SUCCESS) {
			clnt_destroy(client);
			ysd->dom_vers = -1;
			if (r == RPC_PROGUNAVAIL || r == RPC_PROCUNAVAIL) {
				if (new)
					free(ysd);
				return(YPERR_YPBIND);
			}
			fprintf(stderr,
			"YP: server for domain %s not responding, retrying\n", dom);
			goto again;
		} else {
			if (ypbr.ypbind_status != YPBIND_SUCC_VAL) {
				clnt_destroy(client);
				ysd->dom_vers = -1;
				sleep(_yplib_timeout/2);
				goto again;
			}
		}
		clnt_destroy(client);

		bzero((char *)&ysd->dom_server_addr, sizeof ysd->dom_server_addr);
		ysd->dom_server_addr.sin_family = AF_INET;
		ysd->dom_server_addr.sin_port =
			*(u_short *)&ypbr.ypbind_resp_u.ypbind_bindinfo.ypbind_binding_port;
		ysd->dom_server_addr.sin_addr.s_addr =
			*(u_long *)&ypbr.ypbind_resp_u.ypbind_bindinfo.ypbind_binding_addr;

		/*
		 * We could do a reserved port check here too, but this
		 * could pose compatibility problems. The local ypbind is
		 * supposed to decide whether or not to trust yp servers
		 * on insecure ports. For now, we trust its judgement.
		 */
		ysd->dom_server_port =
			*(u_short *)&ypbr.ypbind_resp_u.ypbind_bindinfo.ypbind_binding_port;
gotit:
		ysd->dom_vers = YPVERS;
		strcpy(ysd->dom_domain, dom);
	}

	/* Don't rebuild the connection to the server unless we have to. */
	if (ysd->dom_client == NULL) {
		tv.tv_sec = _yplib_timeout/2;
		tv.tv_usec = 0;
		ysd->dom_socket = RPC_ANYSOCK;
		ysd->dom_client = clntudp_bufcreate(&ysd->dom_server_addr,
			YPPROG, YPVERS, tv, &ysd->dom_socket, 1280, 2304);
		if(ysd->dom_client==NULL) {
			clnt_pcreateerror("clntudp_create");
			ysd->dom_vers = -1;
			goto again;
		}
		if( fcntl(ysd->dom_socket, F_SETFD, 1) == -1)
			perror("fcntl: F_SETFD");
		/*
		 * We want a port number associated with this socket
		 * so that we can check its authenticity later.
		 */
		checklen = sizeof(struct sockaddr_in);
		bzero((char *)&check, checklen);
		bind(ysd->dom_socket, (struct sockaddr *)&check, checklen);
		check.sin_family = AF_INET;
		if (!getsockname(ysd->dom_socket,
		    (struct sockaddr *)&check, &checklen)) {
			ysd->dom_local_port = check.sin_port;
		} else {
			clnt_destroy(ysd->dom_client);
			if (new)
				free(ysd);
			return(YPERR_YPBIND);
		}
	}

	if(new) {
		ysd->dom_pnext = _ypbindlist;
		_ypbindlist = ysd;
	}

	if(ypdb!=NULL)
		*ypdb = ysd;
	return 0;
}

static void
_yp_unbind(ypb)
	struct dom_binding *ypb;
{
	struct sockaddr_in check;
	int checklen = sizeof(struct sockaddr_in);